Manufacture of paper and board



Patented July 20, 1943 MANUFACTURE ormrrn AND noiu'm Sidney Musher, NewYork, N. Y., assignor to Musher Foundation, Incorporated, New York, N.Y., a corporation of New York No Drawing. Application June 5, 1939,Serial No. 277,453

4 Claims. (Cl. a-nas) This invention relates to retarding thedeterioration and the development of ofi and cardboard odors in paperand board and particularly in secondary stock board.

In the field of the secondary stock board made of crude and not toohighly refined raw materials, the board after manufacture is readilysubject to the development of objectionable odors that are transmittedto packaged compositions and particularly when used for the packaging offood products such as for eggs, whole wheat biscults, cakes, cookies andother bakery goods, corn flakes, whole wheat flakes, bacon, and othermeat products, butter, lard, margarine, ice cream, milk, etc.

Even thoughthere is used an inner paper liner,

the objectionable oiT odor penetrates the liner to contaminate thepackaged composition and frequently renders it unsalable. Then developswhat is known as cardboard or papery flavors in eggs, whole wheatbiscuits, etc.

The problem is particularly serious in the utilization of pine stock,and pine board will, within a few days of manufacture and particularlyif fresh stock is employed, develop very objectionable and readilypenetratable oiT-cdors.

An object of this invention is therefore the retardation of cardboardand papery oil-odors andthe substantial stabilization of papers andboards and particularly of pine stock boards.

A further object is to overcome the absorption of objectionable boardodors into packaged organic food compositions, this being accomplishedcheaply and simply.

Still further objectsand advantages will appear from the more detaileddescription setforth below, it being understood, however, that this moredetailed description is given by way of illustration and explanationonly, and not by way of limitation, since various changes therein may bemade by those skilled in the art without departing from the scope andspirit of the present invention.

In accordance with this invention, lecithin is applied to the surface ofpine stock board, for

stock board, for example, is subjected after adding lecithin thereto,the greater is the stabilizing efiect. It is not known as to how thisstabilizing action occurs because it would normally be expected that anelevated temperature decreases rather than increases stability. It isbelieved, however; that some chemical action occurs whereo by markedstabilization is eflected.

The lecithin employed may be of any origin such as from crude corn germoil, cottonseed oil, etc., and obtained by the segregation of thephosphatides from the crude oil. The lecithin may be in its crudeunrefined state or more, highly refined and substantially oil free.

The desirable method for the application of lecithin to the board is toplace the lecithin in a finely divided powdery condition so that it maybe readily stirred into an aqueous bath for application at the calendarstacks. This is accomplished by the use of a carrier such as starch,flour, sugar, powdered skim milk, charcoal, or similar material.

Where starch is employed as, the carrier, for example, a mixture is madecomprising from 50% to 98% by weight of the starch with the balance oflecithin,thoroughly admixing the lecithin in r the powdered starch toobtain a powdery product and one that will readily mix with water eventhough the lecithin is itself not water soluble.

Where the lecithin is more highly refined and freer of associated oil,less of the starch or other carrier need be used to obtain the powderycombination.

The lecithin itself may not readily be applied to the surface of theboard because of its insolubility in water so that if it were added towater for sizing on board, it would not become example, at the calendarstacks and the board tions of the heat treatment, the lecithin at thesurface or the board becomes "activated and develops marked stabilizingcharacteristics.

The higher the temperature to which the pine tain a dispersion of thelecithin in the water which may then be used as a sizing.

The lecithinis desirably present in the water I used for sizing in anamount ranging from 0.3% to 10% against the weight of the water andother materials in the sizing bath, and good results are obtained byusing as'little as 2% of lecithin. Where a lecithin starch mixture isprepared, comprising, for example, starch and 15% lecithin, that mixturemay be added to the water tub at the calendar stacks in an amount of 8%to give desirable improvement to the manufactured board.

Example I Pine stock board after forming an the board making machinecontained 70% total moisture.

The board was passed through a trough contain- I lecithin thoroughlydispersed therethrough. The

starch lecithin mixture was added to the water and the mixture agitatedtohold the combination in suspension while the board passed through, it

j beingestimated that 0.1% by weight of the lecithin adhered to theboard (against the solids weight of the board). The treated board wasthen passed over heated rolls at a temperature of about 220 F. untildried. The board thus obtained was tested alongside of pine stock boardsimilarly prepared but without the lecithin addition by allowing toremain exposed to the air at room temperature and in the dark. Adistinct objectionable cardboard odor developed in the untreated boardwithin 8 days whereas the treated board did not'show the sameobjectionable characteristics until days had elapsed.

The amount of lecithin to apply to the board may vary from 0.01% to2%--but generally less than 0.7% and desirably under 0.3% is applied.

The heating of the board after the addition thereto of the lecithin isimportant to obtain the desired results.

Example II 7 Waste paper stocks used in the manufacture of secondarygrade stock board and containing about 60% total moisture were preparedby adding thereto and thoroughly mixing therein 0.25% against the solidsweight of the board of a mixture comprising 75% lecithin extracted fromcorn germ oil and ,.25% powdered anhydrous dextrose. One sample of thestock thus prepared was heated under 28 pounds of steam pressure for 5minutes. Another sample was heated under 18 pounds steam pressure for 5.minutes. Both lots were then dried in a vacuum oven at 60 C. Thestocksthus prepared were placed into sealed glass bottles and observed forobjectionable odor'development at daily intervals. At the end of 12 daysthe stock which had been heated under 18 pounds pressure was 011 in odorwhereas the stock that was heated under 28 pounds pressure remained ingood condition for about 26 days. t

Pine stock board develops ofi odors rapidly and the lecithin treatmentdescribed in accordance with this invention is particularly valuable forapplication to board made of pine stock and preferably to board made ofpine stock which has not been aged or seasoned" for any long period oftime. For example, the lecithin treatment desirably applies to pinestock board which has been stored and held for less than a 5 monthperiod prior to use.

The treatment described will very materially retard and in many casesprevent the objectionable oiT odors which so seriously depreciate thevalue of that board by contaminating products .packaged in it eventhough the packaged product is not in intimate or direct contact withthe board.

The lecithin is desirably prepared for addition to the paper or boardstock as anoii emulsion and emulsifying agents other than starch orglucose may beused such as gum acacia,

gum tragacanth, blackstrap molasses. etc.

Where the lecithin is emulsified in this manner, it may be put through acolloid mill or an emulsifying machine, in order to reduce the particlesize of the lecithin to as small as possible, so that the lecithin willexert greater effectiveness when utilized in accordance with thisinvention.

The aqueous phase of such an emulsion may desirably include glucose,blackstrap molasses, dextrlnes or gums, and there may also be presentinthat aqueous phase boiled or unboiled starch. 1 g;

Where a powdered mixture is prepared first comprising lecithin andstarch, or lecithin and powdered anhydrous dextrose, sucrose or similarsugar, sumcient cf the starch or sugar serving as the carrier should beutilized so that the finished combination including the lecithin issubstantially in powdered form. In this way it' may be more readilyadded to the size trough or used as a heater application in themanufacture of the board.

Desirable combinations for use are, for example, any of the following:

A. 98 parts'of starch and 2 parts lecithin B. 70 parts powderedanhydrous dextrose and 30 parts lecithin C. 65 parts black strapmolasses lecithin D. 50 parts glucose, 25 parts starch, and 25 partslecithin.

The cruder forms of-lecithin are even more desirable to use inaccordance with this invenand 35 parts tion than the more refinedlecithins. For examdeterioration of pine stock board when particularlysubjected to the elevated temperature is most unusual in view of thefact that lecithin is normally recognized as becoming substantiallyinactivated as an antioxidant when heated to a temperature in excess of65 0., but in accordance with this invention, it has been observed thatunless the high heat treatment is applied, the desired improvement inkeeping quality is not obtained. g,

Where the lecithin is added to a petroleum oil or to paraflln or otherwax used for sizing or impregnation in the paper or board, the desiredeffectiveness of the lecithin is not obtained and, in addition,moisture-proofness is very materially reduced.

Where, however, the lecithin is added to the board without dissolving inthe oil or parailin and where ofled and waxed papers and boards arenormally employed. The'increased paraflin or paraflin oil penetration isoiconsiderable importance in permitting minimum quantities of the oil orparaflin to be employed while getting maximum moisture prooiness andretarding freezer-burn" and 'dessication. As a less preferablealternative to adding the .lecithin as ,a tubsizing operation on theboard or paper, the leeithin may be added in the beaters, provided thatthe paper or board is subsequently subjected to the elevated temperatureof 180 F. to 212 F. and preferably to in excess of 220 F.

The lecithin may be added along with rosin, starches or other materialsthat are normally employed in the heaters and must be thoroughly admixedin the stock material in the heaters in order to obtain a thoroughdispersion of the lec- 'ithin with the paper pulp material.

Although pine board stock is particularly to be treated in accordancewith this invention, other boards may also be treated and alsootherpapers, and particularly kraft, although greaseproof, sulphite, andsimilar papers may be treated in accordance with this invention as well.

Although lecithin may be employed for direct addition to the pine board,either as a tub-sizing or less preferably to the heaters, and suchlecithin may be utilized without the co-addition of starch, sugar orsimilar material, it is most preferable for the lecithin to be addedwith sugar andconsiderably improved results will be obtained when thelecithin-sugar combination is used for addition to the paper stockbei'or'e subjecting it to the elevated temperature as against addinglecithin alone or'even as against a mixture comprising lecithin andstarch.

Eoample III Pine board stock, containing approximately 60%moisture, wastreated by adding thereto and thoroughly mixing therein the followingmaterials:

A. 0.1% soya lecithin B. 0.1% powdered anhydrous dextrose C. Acombination comprising 0.05% soya lecithin and 0.05% powdered anhydrousdextrose D. No addition.

Each of the boards was heated to 220 F. for 10 minutes, and then placedin a vacuum oven at 160 F. until dried. The board stocks were thenplaced in sealed glass bottles andobserved daily for aft odordevelopments.

Oil odor observed after--.

A 18 days B 5 days C 29 days D 4 days Other materials, that may lesspreferably be employed for utilization particularly in retarding thedevelopment of off odors in pine board, include combinations of sugarsor water-soluble carbohydrates, such as dextrins, with any one of thefollowing groups: 1

A. Phospholipins, ."phosphoric acid and phos-' D. Polyhydroxy-arylcompounds such as hydroquinone, pyrogallol, pyrocatechol, resorcinol,phloroglucinol, and other polyhydroxy phenols, guaiacoi, eugenol,aromatic hydroxy aldehydes, the naphthols including alphanaphthol, andsubstituted naphthols, tannic acid, etc.;

E. Other substituted aromatic compounds such as thymol.

Other materials that may be desirably em-fl ployed for addition to paperor board stock, by

themselves or in combination with other materials previously mentioned,and particularly to pine stock in an amount of under 2% include blackstrap molasses and the residues and mother liquors obtained fromthereiining of crude cane and crude beet sugars and less desirably thecrude cane and beet sugars themselves.

The water and alcohol soluble extracts from the cereals and de-oiled orexpressed seeds may also be utilized such as the concentrated waterextract of finely divided dry milled maize, oats or barley, and also andless preferably 'of the seeds such as of peanut, cottonseed, sunflowerseed, olives, etc., and preferably in their de-oiled or de-i'attedcondition and after the glyceride oil contained therein has beenexpressed or extracted therefrom. The water and alcohol soluble extractsof the de-oiled cereal germs may also be employed such as of de-oiledrice germ, corn germ, etc.

These materials may be employed in an amount ranging from 0.005% to 2%against the weight of and for addition to the pine board stock. In anyevent, it is important that the pine board stockbe subjected to theelevated temperature in order to obtain the desired interaction wherebystabilization is secured.

Among the materials that may particularly be employed for addition topine board stock before subjecting to the elevated temperature heatingis tannic acid which appears to be unusual in'having the property ofbecoming markedly increased in stabilizing effect when added to anoxidizable organic compound and particularly to a glyceride, essentialor hydrocarbon oil-containing oxidizable organic compound and thensubjected to an elevated temperature in the presence of that oxidizableorganic compound, such increase in eflectiveness being entirely out ofproportion from what would be expected by comparison to similarlyconstituted are subject to the development of off odors resulting fromthe components of'those textiles being subject to rapid deteriorationunder conditlons of storage.

In the treatment of pine stock board the board may be somewhat improvedin keeping quality by subjecting the pulp to between 30 and 35 poundssteam pressure or more. Where less than 30 pounds steam pressure isapplied to the pulp, the deteriorative changesoccur with extremerapidity but these changes .can be somewhat reduced by subjecting thepulp to between 30 and 35 pounds steam pressure, this treatment beinggiven to the entire pulp before the,

finished board is actually formed, and the pressures indicated isapparently critical in this regard.

The present application is a continuationln part of application, SerialNo. 69,296 filed March 1'7, 1936. i

The pine fiber board of this application, and as referred to in theclaims, relates to the paper and paperboard made of pine stock base,par-'- ticularly by the use of slash pine from which paper andpaperboard of great susceptibility to oxidative deterioration and to thedevelopment of off-odors is obtained. The slash pine used in themanufacture of paper and paperboard becomes more readily subject tooil-odors when it has not been aged or seasoned for a period of three tosix months, and the process described herein is particularly of valuefor paper and paper board made from slash pine and other pine stockwhich has not been properly aged or seasoned. I

Having described my invention, what I claim is l. A process of treatinga pine fiberboard subject to oxidative deterioration which comprisespassing the board through a trough containing an aqueous bath composedof about 93% water and 7% of a starch-lecithin mixture, said mixtureconsisting of about 1 ,part by weight of crude lecithin and about 5parts by weight of starch, and then passing the board over heated rollsat an elevated temperature above 1''. until dry,-the final boardcontaining about between 0.01% and 2% oi lecithin.

2. A'process of treating a paperboard subject to oxidative deteriorationto render the same resistant tooxidative deterioration which comprisespassing the board through a trough containing an aqueous bath composedof a major proportion of water and a minor proportion of a starchlecithin mixture, said mixture consisting'of a minor proportion oflecithin anda major proportion of starch, and then passing the boardover heated rolls at an elevated temperature above 180 F. until dry, thefinal board containing between about 0.01% and 2% of lecithin.

3. A process of treating a pine fibre board subject to oxidativedeterioration to render the same resistant to oxidative deteriorationwhich comprises passing the board through a trough containing an aqueousbath composed of a major proportion of water and a minor proportion of astarch lecithin mixture, said mixture consisting of a minor proportionof lecithin and a major proportion of starch, and then passing the boardover heated rolls at an elevated temperature above 180 F. until dry, theflnal board containing between about 0.01% and 2% of lecithin.

4. A process of treatinga pine fibre board subject to oxidativedeterioration to render the same resistant to oxidativedeterioration'which comprises passing the board through a troughcontaining an aqueous bath composed of about 93% water and 7% of astarchlecithin mixture, said mixture consisting of a minor proportion oflecithin and a major proportion of starch, and then passing the boardover heated rolls at an elevated temperature above 180 F. until dry, thefinal board containing between about 0.01% and 2% oi lecithin.

SIDNEY uusrmn.

